<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>动态粒子效果</title>
    <script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.js"></script>
    <style>
        html,
        body {
            width: 100%;
            height: 100%;
            margin: 0;
            padding: 0;
            overflow: hidden;
        }
        
        .container {
            width: 100％;
            height: 100%;
            margin: 0;
            padding: 0;
            background-color: #000000;
        }
    </style>
</head>

<body>

    <div id="jsi-particle-container" class="container"></div>
    <script>
        var RENDERER = {
            PARTICLE_COUNT: 1000,
            PARTICLE_RADIUS: 1,
            MAX_ROTATION_ANGLE: Math.PI / 60,
            TRANSLATION_COUNT: 500,
            init: function(strategy) {
                this.setParameters(strategy);
                this.createParticles();
                this.setupFigure();
                this.reconstructMethod();
                this.bindEvent();
                this.drawFigure();
            },
            setParameters: function(strategy) {
                this.$window = $(window);
                this.$container = $('#jsi-particle-container');
                this.width = this.$container.width();
                this.height = this.$container.height();
                this.$canvas = $('<canvas />').attr({
                    width: this.width,
                    height: this.height
                }).appendTo(this.$container);
                this.context = this.$canvas.get(0).getContext('2d');
                this.center = {
                    x: this.width / 2,
                    y: this.height / 2
                };
                this.rotationX = this.MAX_ROTATION_ANGLE;
                this.rotationY = this.MAX_ROTATION_ANGLE;
                this.strategyIndex = 0;
                this.translationCount = 0;
                this.theta = 0;
                this.strategies = strategy.getStrategies();
                this.particles = [];
            },
            createParticles: function() {
                for (var i = 0; i < this.PARTICLE_COUNT; i++) {
                    this.particles.push(new PARTICLE(this.center));
                }
            },
            reconstructMethod: function() {
                this.setupFigure = this.setupFigure.bind(this);
                this.drawFigure = this.drawFigure.bind(this);
                this.changeAngle = this.changeAngle.bind(this);
            },
            bindEvent: function() {
                this.$container.on('click', this.setupFigure);
                this.$container.on('mousemove', this.changeAngle);
            },
            changeAngle: function(event) {
                var offset = this.$container.offset(),
                    x = event.clientX - offset.left + this.$window.scrollLeft(),
                    y = event.clientY - offset.top + this.$window.scrollTop();
                this.rotationX = (this.center.y - y) / this.center.y * this.MAX_ROTATION_ANGLE;
                this.rotationY = (this.center.x - x) / this.center.x * this.MAX_ROTATION_ANGLE;
            },
            setupFigure: function() {
                for (var i = 0, length = this.particles.length; i < length; i++) {
                    this.particles[i].setAxis(this.strategies[this.strategyIndex]());
                }
                if (++this.strategyIndex == this.strategies.length) {
                    this.strategyIndex = 0;
                }
                this.translationCount = 0;
            },
            drawFigure: function() {
                requestAnimationFrame(this.drawFigure);
                this.context.fillStyle = 'rgba(0, 0, 0, 0.2)';
                this.context.fillRect(0, 0, this.width, this.height);
                for (var i = 0, length = this.particles.length; i < length; i++) {
                    var axis = this.particles[i].getAxis2D(this.theta);
                    this.context.beginPath();
                    this.context.fillStyle = axis.color;
                    this.context.arc(axis.x, axis.y, this.PARTICLE_RADIUS, 0, Math.PI * 2, false);
                    this.context.fill();
                }
                this.theta++;
                this.theta %= 360;
                for (var i = 0, length = this.particles.length; i < length; i++) {
                    this.particles[i].rotateX(this.rotationX);
                    this.particles[i].rotateY(this.rotationY);
                }
                this.translationCount++;
                this.translationCount %= this.TRANSLATION_COUNT;
                if (this.translationCount == 0) {
                    this.setupFigure();
                }
            }
        };
        var STRATEGY = {
            SCATTER_RADIUS: 150,
            CONE_ASPECT_RATIO: 1.5,
            RING_COUNT: 5,
            getStrategies: function() {
                var strategies = [];
                for (var i in this) {
                    if (this[i] == arguments.callee || typeof this[i] != 'function') {
                        continue;
                    }
                    strategies.push(this[i].bind(this));
                }
                return strategies;
            },
            createSphere: function() {
                var cosTheta = Math.random() * 2 - 1,
                    sinTheta = Math.sqrt(1 - cosTheta * cosTheta),
                    phi = Math.random() * 2 * Math.PI;
                return {
                    x: this.SCATTER_RADIUS * sinTheta * Math.cos(phi),
                    y: this.SCATTER_RADIUS * sinTheta * Math.sin(phi),
                    z: this.SCATTER_RADIUS * cosTheta,
                    hue: Math.round(phi / Math.PI * 30)
                };
            },
            createTorus: function() {
                var theta = Math.random() * Math.PI * 2,
                    x = this.SCATTER_RADIUS + this.SCATTER_RADIUS / 6 * Math.cos(theta),
                    y = this.SCATTER_RADIUS / 6 * Math.sin(theta),
                    phi = Math.random() * Math.PI * 2;
                return {
                    x: x * Math.cos(phi),
                    y: y,
                    z: x * Math.sin(phi),
                    hue: Math.round(phi / Math.PI * 30)
                };
            },
            createCone: function() {
                var status = Math.random() > 1 / 3,
                    x,
                    y,
                    phi = Math.random() * Math.PI * 2,
                    rate = Math.tan(30 / 180 * Math.PI) / this.CONE_ASPECT_RATIO;
                if (status) {
                    y = this.SCATTER_RADIUS * (1 - Math.random() * 2);
                    x = (this.SCATTER_RADIUS - y) * rate;
                } else {
                    y = -this.SCATTER_RADIUS;
                    x = this.SCATTER_RADIUS * 2 * rate * Math.random();
                }
                return {
                    x: x * Math.cos(phi),
                    y: y,
                    z: x * Math.sin(phi),
                    hue: Math.round(phi / Math.PI * 30)
                };
            },
            createVase: function() {
                var theta = Math.random() * Math.PI,
                    x = Math.abs(this.SCATTER_RADIUS * Math.cos(theta) / 2) + this.SCATTER_RADIUS / 8,
                    y = this.SCATTER_RADIUS * Math.cos(theta) * 1.2,
                    phi = Math.random() * Math.PI * 2;

                return {
                    x: x * Math.cos(phi),
                    y: y,
                    z: x * Math.sin(phi),
                    hue: Math.round(phi / Math.PI * 30)
                };
            }
        };
        var PARTICLE = function(center) {
            this.center = center;
            this.init();
        };
        PARTICLE.prototype = {
            SPRING: 0.01,
            FRICTION: 0.9,
            FOCUS_POSITION: 300,
            COLOR: 'hsl(%hue, 100%, 70%)',
            init: function() {
                this.x = 0;
                this.y = 0;
                this.z = 0;
                this.vx = 0;
                this.vy = 0;
                this.vz = 0;
                this.color;
            },
            setAxis: function(axis) {
                this.translating = true;
                this.nextX = axis.x;
                this.nextY = axis.y;
                this.nextZ = axis.z;
                this.hue = axis.hue;
            },
            rotateX: function(angle) {
                var sin = Math.sin(angle),
                    cos = Math.cos(angle),
                    nextY = this.nextY * cos - this.nextZ * sin,
                    nextZ = this.nextZ * cos + this.nextY * sin,
                    y = this.y * cos - this.z * sin,
                    z = this.z * cos + this.y * sin;

                this.nextY = nextY;
                this.nextZ = nextZ;
                this.y = y;
                this.z = z;
            },
            rotateY: function(angle) {
                var sin = Math.sin(angle),
                    cos = Math.cos(angle),
                    nextX = this.nextX * cos - this.nextZ * sin,
                    nextZ = this.nextZ * cos + this.nextX * sin,
                    x = this.x * cos - this.z * sin,
                    z = this.z * cos + this.x * sin;

                this.nextX = nextX;
                this.nextZ = nextZ;
                this.x = x;
                this.z = z;
            },
            rotateZ: function(angle) {
                var sin = Math.sin(angle),
                    cos = Math.cos(angle),
                    nextX = this.nextX * cos - this.nextY * sin,
                    nextY = this.nextY * cos + this.nextX * sin,
                    x = this.x * cos - this.y * sin,
                    y = this.y * cos + this.x * sin;

                this.nextX = nextX;
                this.nextY = nextY;
                this.x = x;
                this.y = y;
            },
            getAxis3D: function() {
                this.vx += (this.nextX - this.x) * this.SPRING;
                this.vy += (this.nextY - this.y) * this.SPRING;
                this.vz += (this.nextZ - this.z) * this.SPRING;

                this.vx *= this.FRICTION;
                this.vy *= this.FRICTION;
                this.vz *= this.FRICTION;

                this.x += this.vx;
                this.y += this.vy;
                this.z += this.vz;

                return {
                    x: this.x,
                    y: this.y,
                    z: this.z
                };
            },
            getAxis2D: function(theta) {
                var axis = this.getAxis3D(),
                    scale = this.FOCUS_POSITION / (this.FOCUS_POSITION + axis.z);
                return {
                    x: this.center.x + axis.x * scale,
                    y: this.center.y - axis.y * scale,
                    color: this.COLOR.replace('%hue', this.hue + theta)
                };
            }
        };
        $(function() {
            RENDERER.init(STRATEGY);
        });
    </script>
</body>

</html>